The invention relates to a drafting unit for a spinning machine having a loading support which is pivotable around a supporting rod extending in parallel with respect to bottom rollers and can be locked in its operative position and which has two arms extending parallel at a distance from one another, which accommodate holding devices for shafts of pressure rollers which are constructed as pressure roller twins assigned to two adjacent spinning points, and having a pivotable cover covering the loading support.
In the case of a known drafting unit of the initially mentioned type (DE-C 32 09 210), the two arms of the loading support are each separately pivotable and can each be locked separately. In the known construction, a cover is also provided which covers the two arms and the area located in between. This cover is mounted at locking levers of which one is in each case assigned to one of the arms. The area of the pressure rollers is covered by additional flaps which can be pivoted separately. It is not possible to swivel the cover open without interrupting the operation of the drafting unit.
It is also known (DE-C 31 43 215) to provide a loading support manufactured as a cast part which has two guides respectively for the pressure rollers and one loading device which is arranged in the center between them. In this construction, the locking of the loading support in the operative position takes place by means of a locking device arranged at the end of the loading support facing away from the holding rod.
An object of the invention is to develop a drafting unit of the initially mentioned type such that the loading support can have a sturdy construction and that the area of the drafting unit can be made accessible for a cleaning without the requirement of moving the loading support out of its operative position.
This object is achieved according to preferred embodiments of the invention in that the two arms of the loading support are-connected at their ends by means of cross-struts to form a frame which, in the area of one cross-strut, is disposed on the supporting rod, and in that the cover is disposed such that it can be swivelled away when the the loading support is locked in its operative position.
As a result of the frame construction, the support has a high stability. Nevertheless, it is not necessary to provide two independent bearings and locking devices. In addition, it is possible to swivel the cover away without having to also swivel the loading support. As a result, it is possible to make the area of the loading support and also the interior area of the cover accessible to a cleaning by means of a suction nozzle or a blowing nozzle without the requirement of interrupting the operation of the drafting unit.
In a further development of preferred embodiments of the invention, it is provided that the loading support with the parallel arms and the cross-struts is constructed as a punched and edged sheet-metal profile. This permits a relatively light but still very stable construction.
In a further development of preferred embodiments of the invention, a locking device for the loading support is provided which is applied to the cross-strut facing away from the supporting rod. As a result, the operative position is locked securely while the forces distribute themselves more evenly.
In an expedient development of preferred embodiments of the invention, it is provided that the cover, covers the locking device in its covering position. As a result, a smooth outer contour is made possible. In this case, it is provided in an expedient further development that the cover covers the loading support and the pressure rollers held by it. The covers, which are assigned to two spinning points respectively, thus cover the whole drafting unit area so that a closed streamlined design is obtained.
In a further development of preferred embodiments the invention, it is provided that the cover is disposed such as the loading support that it can be pivoted around a swivelling axis which is in parallel to the supporting rod and that it can be locked at the loading support in its covering position. In this development, the loading support and the cover form a structural unit which, if required, can be demounted as a whole and, if necessary, can be exchanged for a new loading support with a cover.
In order to shield the operating side from the noises caused by the drafting unit, it is provided in a further development of the invention that the cover, preferably on its interior side, is provided with noise-suppressing material.
In a further development of preferred embodiments of the invention, it is provided that the cover is equipped with cleaning devices assigned to the pressure rollers which can be swivelled away from the pressure rollers together with the cover. The cleaning devices can therefore be swivelled away from the pressure rollers together with the cover without the necessity of interrupting the operation of the drafting units. It is therefore possible to also make the cleaning devices accessible to a cleaning without interrupting the operation.
In a further development of preferred embodiments of the invention, it is provided that the cleaning devices contain cleaning rags constructed as continuous loops, these cleaning rags each moving around a roller which is coaxial with respect to the swivelling axis of the cover. As a result, it is possible to drive the cleaning rags by way of the rollers which are coaxial with respect to the swivelling axis without impairing the swivelling-away of the cover.
In a further development of preferred embodiments of the invention, it is provided that the cover is equipped with a suction device which contains suction nozzles assigned to the cleaning devices and which is equipped with a section piece which, in the covering position of the cover, connects to a suction pipe. This suction device is therefore arranged in such a manner that it also does not interfere with the swivelling-away movement of the cover.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.